Re: [PATCH v3 1/4] ACPI: PM: Drop parent state update from acpi_device_get_power()

[sashiko-bot@kernel.org]

> From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
> 
> The parent state update in acpi_device_get_power(), that occurs when the
> child device turns out to be in D0 and the parent's power state is still
> unknown, is highly questionable because it may cause the reference
> counters of the power resources used by the parent in D0 (if any) to
> underflow when the parent goes into a low-power state later.  Moreover,
> there is no reason to do it on reads from the real_power_state sysfs
> attribute of the child.
> 
> That check had been added by commit 8f7412a792bc ("ACPI / PM: Infer
> parent power state from child if unknown, v2") before starting to
> handle the "missing _PSC and no power resources" case directly in
> acpi_bus_init_power(), as of commit b3785492268f ("ACPI / PM: Do not
> power manage devices in unknown initial states").  It is not necessary
> any more and commit b3785492268f should have removed it.
> 
> Drop it now.
> 
> Fixes: b3785492268f ("ACPI / PM: Do not power manage devices in unknown initial states")
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/6044499.DvuYhMxLoT@rafael.j.wysocki?part=1